This invention relates generally to a method and apparatus for controlling the movement of an extendable stick on a work machine and, more particularly, to a method and apparatus for coordinating the movement of an extendable stick with the movement of a stick on the work machine.
Work machines having multiple linkages with multiple degrees of movement are commonly used for various tasks. For example, in earthworking applications, work machines such as backhoe loaders, excavators and shovels have multiple linkages which are used to controllably move a work implement, such as a bucket, scraper, hammer, hoist and the like.
A backhoe loader, for example, typically includes a boom, a stick pivotally attached to the boom, and a work implement such as a bucket pivotally attached to the stick. An operator of such a machine controls the movements of the boom, stick and bucket in coordination with each other to controllably perform a work task, such as digging, trenching or dredging. Usually the operator controls the movement of these linkages by the use of control levers, one for each linkage. A skilled operator can usually coordinate all of the control levers in a manner which efficiently controls the work implement as though all of the linkages operated as one unit.
There are situations in which the linkages do not provide the reach needed to perform certain tasks. For example, if it is desired to dig very deep, or to extend the work implement a great distance from the work machine, the physical constraints of the linkage components may not suffice for the work needed. Consequently, one solution has been to develop a stick linkage that extends; that is, an extendable stick. Extendable sticks are known for use with backhoe loaders, excavators, and other types of machines. Although an extendable stick provides a greater reach for the work implement, an additional control lever is required, thus making a complex and difficult control task even more difficult, even for a skilled operator. It is desired, therefore, to provide the greater reach capabilities of a work machine having an extendable stick, yet avoid the additional complexity involved with control of the work implement.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention a method for automatically controlling the movement of an extendable stick on a work machine is disclosed. The extendable stick is slidably connected to a stick, and the stick is pivotally connected to a boom The method includes the steps of determining a position of the stick relative to the boom, determining a position of the extendable stick relative to the stick, receiving a stick movement command to move the stick relative to the boom, moving the stick relative to the boom, and moving the extendable stick in coordination with the movement of the stick as a function of a desired position of the extendable stick relative to the position of the stick.
In another aspect of the present invention an apparatus for automatically controlling the movement of an extendable stick on a work machine is disclosed. The extendable stick is slidably connected to a stick, and the stick is pivotally connected to a boom. The apparatus includes means for determining a position of the stick relative to the boom, means for determining a position of the extendable stick relative to the stick, means for receiving a stick movement command to move the stick relative to the boom, means for moving the stick relative to the boom, and means for moving the extendable stick in coordination with the movement of the stick as a function of a desired position of the extendable stick relative to the position of the stick.
In yet another aspect of the present invention an apparatus for automatically controlling the movement of an extendable stick on a work machine is disclosed. The extendable stick is slidably connected to a stick, and the stick is pivotally connected to a boom. The apparatus includes a first sensor for determining a position of the stick relative to the boom, a second sensor for determining a position of the extendable stick relative to the stick, and a controller for receiving a stick movement command to move the stick relative to the boom, for moving the stick, and for moving the extendable stick in coordination with the movement of the stick as a function of a desired position of the extendable stick relative to the position of the stick.
In yet another aspect of the present invention a method for controlling the movement of an extendable stick on a work machine is disclosed. The extendable stick is connected to a stick, and the stick is pivotally connected to a boom. The method includes the steps of selecting one of a manual control mode and a coordinated control mode, operating each of a stick control device and an extendable stick control device to control the respective movement of each of the stick and the extendable stick in response to selecting the manual control mode, and operating only the stick control device to control the movement of the stick and the extendable stick in response to selecting the coordinated control mode, the movement of the extendable stick being made in coordination with the movement of the stick as a function of a desired position of the extendable stick relative to the position of the stick.
In yet another aspect of the present invention a work machine is disclosed. The work machine includes a boom, a stick having a first end pivotally connected to the boom, an extendable stick having a first end slidably connected to a second end of the stick, a work implement controllably attached to a second end of the extendable stick, a first sensor for determining a position of the stick relative to the boom, a second sensor for determining a position of the extendable stick relative to the stick, a stick control device for delivering a stick movement command, and a controller for receiving the stick movement command and responsively moving the stick relative to the boom, and for moving the extendable stick in coordination with the movement of the stick as a function of a desired position of the extendable stick relative to the position of the stick.